Dragon scales have a mirrored surface, so the laser will reflect.
Why is that? It has quite specific properties.
The authors are not involved here; we're just discussing the facts.
I'll repeat again: A mirror won't protect you from a laser.
Bow down and hear our cry,
Our earthly rulers falter,
Our people drift and die,
The walls of gold entomb us,
The swords of scorn divide,
Take not thy thunder from us,
Take away our pride.
G.K. Chesterton: English Hymnal